Placed floorstanders on 2" concrete slab - less bass

Discussion in 'Archived Threads 2001-2004' started by ChrisAG, Apr 17, 2002.

  1. ChrisAG

    ChrisAG Supporting Actor

    Joined:
    Aug 26, 2001
    Messages:
    503
    Likes Received:
    0
    Due to unavoidable room layout, one of my Mordaunt-Short 906 towers was partly obscured by a couch arm, which completely hid the bottom woofer and partly hid the midrange. Sound was definitely compromised because of this, though the speakers sounded good otherwise, with decent bass. They have floor spikes, and were on a carpeted floor.

    In an attempt to remedy this I bought a couple of one foot square concrete patio stones and placed them under the speakers, keeping the spikes. Sound clarity improved, but now there is less bass. I think the firm connection with the floor has been lost.

    The speakers have balast chambers for sand, which I have not used. Would this help? If not, are there any other things I could try to restore the bass?
     
  2. Paul Clarke

    Paul Clarke Supporting Actor

    Joined:
    Jan 29, 2002
    Messages:
    998
    Likes Received:
    0
    In this situation I would remove the spikes. You may also experiment with replacing the support underneath from a solid square to a more open rectangle platform framing the speaker bottom. This of course would require new support material. I tried this with good effect in a similar situation.

    First remove the spikes. If unsatisfactory...

    Fill with sand. If unsatisactory...

    Try the different support design. You can always go back to where you started. Good Luck.
     
  3. Hanwook_K

    Hanwook_K Stunt Coordinator

    Joined:
    Dec 2, 2000
    Messages:
    83
    Likes Received:
    0
    Is it that the bass is gone or that it was muddy before? Sometimes what you hear as less bass is actually more acurate bass ... just being devils advocate.
     
  4. Robert_Dufresne

    Robert_Dufresne Stunt Coordinator

    Joined:
    Mar 30, 2002
    Messages:
    246
    Likes Received:
    0
    I agree with Hanwook. Maybe less is more but I would
    definitely remove the spikes. Spikes are great for
    hardwood or carpetted floors but are not great on
    concrete . The goal is to minimise cabinet vibration
    so filling with sand should help.
    Good luck [​IMG]
    Robert
     
  5. MarkO

    MarkO Second Unit

    Joined:
    Feb 19, 1999
    Messages:
    309
    Likes Received:
    0
    When you raised youre speakers higher off the floor you lost some of the "floor reflection" and youre bass thined out because of it.
     
  6. ChrisAG

    ChrisAG Supporting Actor

    Joined:
    Aug 26, 2001
    Messages:
    503
    Likes Received:
    0
    The bass wasn't muddy before, it was nice and tight. I think the spikes on concrete did not allow a good "anchor" like the floor did. I've removed the spikes but kept the outrigger feet, and have placed thin rubber matting between the concrete and feet. I haven't cranked it up yet, but it seems to be a better platform. I'll test it this weekend.

    As for the increased distance of the driver from the floor reducing the bass, that may be partly true, but I think the anchor theory above is more sound in this case (pardon the pun). I agree that filling the bottom of the speakers with sand should help also.

    Thanks everyone for your input.
     
  7. BruZZi

    BruZZi Second Unit

    Joined:
    Nov 1, 1999
    Messages:
    327
    Likes Received:
    0
     
  8. Frank_S

    Frank_S Supporting Actor

    Joined:
    Oct 28, 1999
    Messages:
    565
    Likes Received:
    0
    Chris, I did a similar thing, had my N804's on top of concrete slabs but I actually spiked the slabs to the subfloor.

    I did'nt like the performance with concrete so I bought some 1" thick ash and finished and stained them to match my N804's. I have the ash platforms spiked to my subfloor and my speakers spiked to the ash platforms. I have a very rigid setup and get very tight bass response now. I think wood makes a better platform than concrete.
     
  9. ChrisAG

    ChrisAG Supporting Actor

    Joined:
    Aug 26, 2001
    Messages:
    503
    Likes Received:
    0
    Frank,

    Is "Ash" a specific wood type, and where did you buy it? Can it dry out and warp over time?
     

Share This Page